It is important to periodically make backup copies of internally stored computer files to ensure that no information is lost if the original file is destroyed, such as can occur if a computer hard disc crashes. If the files are relatively small in size, the backup copy can be conveniently and quickly made using one or more floppy discs. The data storage capability of personal computers and local area networks has increased sufficiently that it is impractical to store the large quantity of computer data on floppy discs. As such, magnetic tape has been used to store backup copies, with the magnetic tape taking the form of a tape cassette. One such backup system is disclosed in U.S. patent application No. 07/410,136, filed Sep. 20, 1989, and entitled APPARATUS AND METHOD FOR AUTOMATIC STORAGE OF COMPUTER DATA.
Additionally, due to the increasingly large number of computer files used by computers and the limited local high speed disc memory available, it has become necessary to provide large volume, extended storage capability not utilizing the local memory. For example, the hard disc memory of all computers can only be used to store so many files before the memory becomes full or access time increases to an unacceptable level. Thus, it is desirable to provide external storage for computer files other than for backup purposes.
For various reasons, the use of digital audio tape (DAT) cassettes for storing computer files is desirable. These cassettes have a design that differs from existing tape cassettes used for file storage and require a specially constructed storage unit. The present invention provides such a storage unit.